There are strong and differing opinions on the relative merits and potential consequences associated with manure irrigation in Wisconsin—ranging from outrage over perceived risks to advocacy for its advantages. Here are some of the key issues shared with the workgroup when it began:
Those supporting manure irrigation practices suggest that application of manure and process wastewater through irrigation equipment offers several advantages over other forms of manure distribution:
- An ability to distribute manure during the growing season, instead of more concentrated applications in spring and fall
- An ability to control (with precision) the timing, amount, and location of nutrients to crops during the growing season when plants are using the nutrients
- The potential for less risk of surface runoff during storm events due to controlled timing of application
- The potential for reduced nutrient leaching below the root zone due to plant uptake of nutrients during growing season
- Lower distribution costs for producers compared to manure haulers/tankers
- Reduced risk of manure spills compared to manure haulers/tankers
- Reduced traffic volume and damage to roads from manure haulers/tankers
- Reduced soil compaction on fields
Those opposed to manure irrigation practices express deep concerns about farms applying manure and process wastewater through irrigation equipment, consistent with these themes:
- The full extent of health and quality of life risks are unknown and potentially severe.
- Health concerns that aerosol spray drift from manure irrigation could carry pathogens, particulates, antibiotics, endocrine disruptors, cleaning compounds, toxic gases (hydrogen sulfide and ammonia), and ‘super bacteria’ including LA-MRSA. Concerns that contaminants could affect the general population and especially those with compromised immune systems and elderly; concerns that those negative health effects could be magnified because aerosols penetrate lungs and carry toxins to the bloodstream more directly than if ingested.
- Quality of life concerns, reinforced by reports from people who have complained of worsening respiratory health, poor air quality, increased airborne particulates, odor, and contamination of their property as a result of nearby manure irrigation.
- The potential for contamination of surface water and wells from irrigation application, especially in areas where access to groundwater is more direct such as in sandy soil or karst. There are concerns about runoff from precipitation events after manure irrigation application.
- Groundwater quantity concerns that manure irrigation might use excessive amounts of groundwater resources and may draw down wells.
- There are concerns that existing and future setbacks will be inadequate to protect neighbors, surface waterways, and crops in nearby fields.
- Organic farms are concerned about the risk of losing organic certification due to spray drift depositing materials on crops.
- There are concerns that monitoring implementation of manure irrigation practices would be difficult and impractical.
These expressed benefits and concerns helped shape the agenda for the workgroup. Throughout its activities, the workgroup welcomed public input. There has been relatively little available research on the actual aerosol drift and related effects of manure irrigation. Research reports and web-links to existing information can be found at the “resources” page of this website.
For more information about these issues, view the presentations from the public symposia, found here: public symposia